In May 2007, a BBC Panorama programme caused shockwaves within the educational IT world by suggesting that Wi-Fi wireless networks could be harming children's health. The programme, Wi-Fi - a Warning Signal, performed tests which purported to show that Wi-Fi laptops emitted much higher levels of radiation than a mobile phone mast, interviewed scientists who claimed that Wi-Fi networks could be harmful, and included people saying radiowaves had adversely affected their health, causing headaches and other symptoms.

Little wonder then, that many parents and teachers were concerned over the use of Wi-Fi networks in schools, especially now that more than two thirds of secondary and more than half of primary schools have them. What's more, Wi-Fi hotspots are springing up in all kinds of public places including libraries, railway stations and coffee shops. "It certainly caused a number of people to worry and we know of at least one parent who provided their school with an inch-thick dossier of material gathered from websites against Wi-Fi," says Tim Pearson, chief executive of ICT supplier RM. Tottenham council even considered banning the use of wireless technology in schools.

However Brian Lightman, president of the Association of School and College Leaders (ASCL) says that statements released by the educational technology agency Becta and the Health Protection Agency after the Panorama programme (HPA) helped to reassure teachers. The agency says: "On the basis of the studies so far carried out in-house, the HPA sees no reason why Wi-Fi should not continue to be used in schools." Lightman states that he is not aware of any ASCL member changing their approach to Wi-Fi, as a result of the Panorama programme.

But he adds: "What we do say is that wireless on its own may not be the best technology for providing access to school networks and websites."

Take heart from the Thomas Deacon city academy in Peterborough, which opened last September and has recently installed a wireless network. "I read all that I possibly could on the subject and then decided to go ahead with Wi-Fi," says Steve Warburton, director of innovation and development. "There have been no concerns raised by parents, pupils or staff."

Makers of Wi-Fi equipment and networks report no slowdown in sales following the TV programme. "It's had no noticeable impact on sales," says Peter Airs, channel manager at Netgear. RM's Pearson says there has been no sign of schools changing their purchasing decisions when it comes to wireless networking. Chris Davies, general manager of D-Link - a developper and manufacturer of corporate networking solutions - says: "the inherent benefits [of wireless for schools] are huge. Schools want their students to have the mobility that wireless offers and they also see it as a way of reaching the wider community."

Many fears over Wi-Fi will have been calmed by a statement issued by the BBC's editorial complaints unit (ECU) following complaints about the Panorama programme. The unit said Panorama had given an unbalanced impression of the state of scientific opinion and wrongly suggested that Wi-Fi networks emitted a higher level of radiation than mobile phone masts.

"It's good that the BBC came to this conclusion but rather sad that they gave far less publicity to the ECU's conclusions than they did to the original programme, which even got coverage on the six o'clock news," says Pearson.

The intense interest over Wi-Fi and safety resulted in the HPA announcing last October the launch of a two-year "systematic" programme of research on the radiation emission levels of wireless networks, especially in schools. At the time HPA chief executive Pat Troop said: "There is no scientific evidence to date that Wi-Fi... adversely affect[s] the health of the general population. The signals are very low power and... given this, there is no particular reason why schools and others should not continue to use Wi-Fi or other wireless networks."

His words have not reassured everyone. Philip Parkin, general secretary of the Professional Association of Teachers has warned that pupils are being used as guinea pigs until research establishes that Wi-Fi networks are safe. He's also critical of the HPA's planned investigation: "They're not going to inquire into the right things," he claims. "For instance, they're limiting the study to the thermal effects [the heating effect of radiowaves], rather than looking at non-thermal effects, like headaches and nausea."

But Michael Clarke, HPA's scientific spokesman, defends this strategy: "Before you do anything, you need basic data and that's what this study will provide. Is there more exposure to radiowaves when there are 30 children using a laptop than 20? Does it make much difference if the laptop is on a desk or on your lap? We simply don't know at this stage."

RM's Pearson says it's right that further research is carried out into Wi-Fi safety, especially where children are involved. "It's worth a closer look, but we should have a sensible and rational debate about Wi-Fi."